Organic Chemistry ACS Sample Questions

ACS Examination guide (Selected Questions)Organic ChemistryNomenclature1. What is the IUPAC names for this compound?a) 1-tert-butyl-2-butanolb) 5,5-dimethyl-3-hexanolc) 2,2-dimethyl-4-hexanold) 1,1,1-trimethy-3-pentanol4.What is the IUPAC name for this structure?a) 3-bromo-4-methylheptanoneb) 5-bromo-4-methylheptanonec) 5-bromo-4-methyl-3-heptanoned) 3-bromo-4-methyl-5-heptanone9. What is the IUPAC name of this compound?a) m-hydroxy-m-xyleneb) 3,5-dimethylphenolc) 2,4-dimethyl-6-hydroxybenzened) 3-hydroxy-5-methyltolueneAnswer: 1, b; 4, c; 9, b.

Structure, Hybridization, Resonance, Aromaticity Chapter Book p 17,18,191) identify the lowest-energy Lewis structure for nitrogen oxide. (Formal charges notshown.)8) The heat of combustion (per CH2) of several cycloalkanes is listed below. Based onthe data given, which of these cycloalkanes would be considered most stable.a) cyclobutaneb) cyclopentanec) cyclooctaned) cyclopentadecane11) Which pair consists of the resonance structure?Answer: 1, c; 8, d;11, a

Organic Chemistry (/organic-chemistry/practice-problems) / Factors Affecting Acidity Overview nd cidity)Book P 30, 31ConceptSolutions281. Which structure corresponds to the predominant form of this molecule near pH 7?1x1.25x1.5x1.75xSolution: Which is the order from the strongest acid to the weakest ac.Question4.Whichis theorderthe strongestto the weakestacid forthese species?Whichis theorderfromfromthe strongestacid toacidthe weakestacid for thesespecies?A) II IV I IIIB) III I IV IIC) III IV I IID) II I IV III2x

Stereoisomerism Book P38, 39,1) Which molecule has the R configuration?6) Which Newman projection represents the most stable configuration of(CH3)2CHCH(CH3)2Answer: 1, c;4, a;8, d.8) Which of the indicated protons in this compound would have the smallest pKavalues?

10) Which diastereoisomer is most stable?Answer: 1, c; 6, c, 10, b.

Nucleophilic Substitution and Elimination2) When 2-bromo -2-methybutane is treated with a base, a mixture of 2-methyl-2-buteneand 2-methyl-1-butene is producedWhen potassium hydroxide is the base, 2 methyl-1-butene accounts for 45% of themixture, but when potassium tert-butoxide is the base, 2 methyl-1-butene accounts for70% of the mixture. What would you predict for the percent of 2 methyl-1-butene in themixture if the potassium prop-oxide were the base?(a) Less than 45%(b) 45%(c) between 45% and 70%(d) more than 70%

11) Why would the concentrated hydrobromic acid be an inappropriate catalyst for thedehydration of alcohols?a) HBr is too weakly acidic to protonate the alcohol.b) The conjugate base, Br - , is a good nucleophile and it would attack the carbocationto form an alkyl bromide.c) HBr is strongly acidic, so the water molecule would not be a good leaving group afterprotonation of the alcohol.d) HBr would be more likely to promote rearrangement of the carbocation intermediate.17) What would be the first step in the dehydration of cyclohexanol in sulfuric acid?a) loss of OH b) loss of H by the alcoholc) formation of a sulfite esterd) protonation of the alcoholAnswer: 2, c, 11, b, 17, d.

Electrophilic Additions7) which set of the reagents will carry out the conversion shown?Answer: 7, cNucleophilic Addition at Carbonyl Groups8) which compound would be most rapidly hydrolyzed by aqueous HC to give methanolas one of the products?

12) which is the best reagent for this conversion?17) which reagent will accomplish the conversion shown?Answer: 8, d, 12, b, 17, d.

Nucleophilic Substitution at Carbonyl Groups1) This reaction that is typical of carboxylic acids, ester, acid halides, anhydrides, andamides is called.(a) nucleophilic non-acyl substitution(b) nucleophilic addition(c) nucleophilic acyl substitution(d) electrophilic substitution3) Which would be hydrolyzed most slowly with aqueous NaOH?

13) Which reaction sequence is preferred for this conversation?Answer: 1, c, 3, a, 13, b.Enols and Enolate Ion Reactions pg. 9716) The first two steps in the base-catalyzed condensation of acetaldehyde would bedescribed as:–D) OH abstracts the hydrogen atom from the carbonyl carbon, the then resultant anionthe carbonyl carbon atom on a second molecule of acetaldehyde.attacks

20) Which represents a keto-enol tautomerization?24) What is the product formed from this reaction?Answer: 16, c; 20, d; 24, d.

Electrophilic and Nucleophilic Aromatic Substitutions pg.1141. Which substituents would deactivate benzene toward electrophilic aromaticsubstitution reaction?4. Which set of reagents would most likely bring about this transformation?Answer: 1, b; 4, a.

Free-Radicals Substitution and Additions1.Which radical is the least stable?5. What is the expected product of this reaction?Answer: 1, b; 5, c.

Oxydation and Reduction pg. 1381.which reagents are best for carrying out this reaction?3. Which reagents would best accomplish this transformation?

6. reduction of a triple bond to a E (trans) double bond can be accomplished with wichset of reagents?Answer: 1, a; 3, c; 6, a.

Spectroscopy1. Which ketone will show a carbonyl absorption at the lower frequency (cm-1) in theinfrared?

3. Which is the reasonable structure for a compared with this IR spectrum?

5. Which structure is most consistent with this IR spectrum?Answer: 1, b; 3, a; 5, d.

Synthesis and Qualitative Analysis12. Which would be a suitable solvent for the preparation of ethyl-magnesiumbromide from ethyl bromide and magnesium?14. Which reaction sequence might be used to synthesize this compound?Answer: 12, c; 14, a.

Organic Chemistry Nomenclature 1. What is the IUPAC names for this compound? a) 1-tert-butyl-2-butanol b) 5,5-dimethyl-3-hexanol c) 2,2-dimethyl-4-hexanol d) 1,1,1-trimethy-3-pentanol 4.What is the IUPAC name for this structure?